This paper uses a unique dataset of long‐run migration in China to provide new measures of cultural distance based on biological evidence. We utilise this information to examine the effect of cultural distance on migration in China from the Song Dynasty until the twentieth century. Our findings show that culture has strong effects on migration between regions when controlling for other socio‐economic and geographical factors. Population flow is greater where there are fewer cultural differences. This finding not only provides quantitative empirical evidence on linking cultural distance and migration but also leads to a better understanding of the mechanisms resulting in migration for much of China's history.